Heart surgery usually requires stopping the heart so as to obtain a stationary and exsanguinous operating site allowing a precise and delicate surgical operation. This entails: 1) resorting to extra-corporeal circulation (ECC) so as to perfuse the systemic organs (brain, liver, kidneys, etc.) with oxygenated blood for the period during which the heart is stopped.
2) clamping the aorta, which consists in blocking the vessel using external forceps which are applied between the arterial cannula allowing extra-corporeal circulation and the orifice of the coronary arteries. This operation isolates the coronary circulation from the blood flow supplied by the ECC and therefore allows the heart to be stopped.
3) Cardioplegy: injection of a solution into the network of coronary arteries to protect the heart itself during the period of arrest.
Hooking up the extra-corporeal circulation (ECC), clamping and cardioplegy conventionally entail cutting and parting the sternum (sternotomy). Sternotomy is a destructive surgical approach that carries significant post-operative risks to the patient.
Furthermore, clamping the aorta is an operation which is considered to be delicate and high risk because, in particular, of the proximity of the pulmonary artery, the texture of which is known to be extremely fragile.
What is more, clipping the artery using a conventional clamp is a source of embolism of atheromatous material which, in most cases, lines the internal wall of the vessel.
For many years, heart surgery has been developing alternative techniques aimed at being less aggressive toward the patient. Doing away with the sternotomy is one of these approaches. In this case, the operation is carried out using mini-incisions allowing endoscopic instruments to be introduced.
In this type of operation, when the heart needs to be stopped, an inflatable balloon is introduced into the aorta, where it leaves the heart, under echographic or fluoroscopic guidance, to clamp the aorta from inside the vessel.
This system has numerous disadvantages including, in particular, its cost, which limits its use to a number of marginal cases. Furthermore, this technique also dislodges particles carried along by the blood flow.
There is no alternative at the present time which is able to interrupt the circulation of the blood in the aorta without opening up the thorax.